Genetic consequences of blocking polar body I with cytochalasin B in fertilized eggs of the pacific oyster, crassostrea gigas: I. ploidy of resultant embryos

Ximing Guo, Kenneth Cooper, William K. Hershberger, Kenneth K. Chew

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

The effect of blocking polar body I (PB 1) with cytochalasin B (CB) on the ploidy of embryos was studied in the Pacific oyster, Crassostrea gigas. To block the release of PB 1, fertilized eggs were treated with CB (1.0 μg/ml) for 15 min beginning at 5 min post-fertilization at 25°C. The CB treatment and its control were repeated in three crosses. Ploidy of 8-h-old embryos was determined with karyological analysis. In control groups, the majority of the cells (89.3%) had a diploid number of 20 chromosomes, although spontaneous haploids (0.7%), triploids (1.3%) and aneuploids (8.7%) were also encountered. In CB-treated groups, only 4.5% of the cells remained as diploid, and the majority were either triploid (15.6%), tetraploid (19.4%) or aneuploid (57.6%). Despite variation among the three crosses, contingency Chi-square analysis showed that the occurrence of triploids, tetraploids and aneuploids had a significant (P = 0.0001) dependence on the CB treatment. The majority of the aneuploids fell into two groups containing either 23-25 or 35-37 chromosomes. The production of triploids, tetraploids and aneuploids in specific distributions suggests that blocking PB 1 complicates subsequent chromosome segregation.

Original languageEnglish (US)
Pages (from-to)381-386
Number of pages6
JournalBiological Bulletin
Volume183
Issue number3
DOIs
StatePublished - 1992
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Agricultural and Biological Sciences(all)

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